This invention relates to improved apparatus and methods for the treatment of prostate cancer. More particularly, the present invention provides a needle template mount that provides for angular reorientation of a needle template for more effective administration of brachytherapy.
Excluding nonmelanoma skin cancers, prostate cancer is the most common cancer afflicting American men. The American Cancer Society estimates that over 180,00 new cases will be diagnosed in the U.S. in the year 2000 alone, and that nearly 32,000 people will die from the disease. Prostate cancer is second only to lung cancer as the leading cause of cancer death in men, accounting for roughly 11%.
Prostate cancer is defined as malignant tumor growth within the prostate gland. Its cause is unknown, although high dietary fat intake and increased testosterone levels are believed to be contributory factors. A letter scale (xe2x80x9cAxe2x80x9d through xe2x80x9cDxe2x80x9d), which accounts for aggressiveness and differentiation, is commonly used to classify the stage of disease. In Stage A, the tumor is not palpable but is detectable in microscopic biopsy. Stage B is characterized by a palpable tumor confined to the prostate. By Stage C, the tumor extends beyond the prostate with no distant metastasis. By Stage D, cancer has spread to the regional lymph nodes.
In the early stages, prostate cancer is most commonly treated by prostate removal or by brachytherapy. More advanced cases are treated by hormonal manipulation or orchiectomy to reduce testosterone levels and curb spreading of the disease, by chemotherapy, or by external beam radiation therapy.
With regard to treatment of early stage prostate cancer, the state of the art has several drawbacks. Radical prostatectomy is often recommended for treatment of localized stage A and B prostate cancers. Under general or spinal anesthesia, an incision is made through a patient""s abdomen or perineal area, and the diseased prostate is removed. The procedure is lengthy, especially if a lymph node dissection is simultaneously performed, and requires a hospital stay of 7-10 days. Possible complications include impotence and urinary incontinence.
Internal radiation therapy or brachytherapy has recently been developed and holds great promise for the treatment of early stage prostate cancer. Radioactive pellets or seeds of, for example, iodine-125, palladium-103, or iridium-192, are deposited directly and permanently into the prostate through a small incision. Imaging techniques, such as transrectal ultrasound, CT scans, or MRI, are used to accurately guide placement of the radioactive material. Advantageously, radiation from the brachytherapy seeds is administered directly to the prostate with less damage to surrounding tissues, delivering a substantially higher radiation dosage to the prostate than to the surrounding tissues, as compared to external beam radiation therapy. The procedure need only be performed once, and impotence and urinary incontinence complications are significantly reduced, as compared to prostate removal procedures.
The radioactive seeds are placed inside thin needles, which are inserted through the skin of the perineum (area between the scrotum and anus) into the prostate. U.S. Pat. No. 5,928,130 Schmidt provides a slightly modified example of such a needle device. Each needle is slowly retracted with a spinning motion by a first practitioner while a plunger within the needle, and proximal of the radioactive seeds, is held stationary by a second practitioner. The plunger keeps the seeds in place during retraction of the needle, while rotation of the needle during retraction delivers the seeds in a line within the prostate.
The seeds, which are permanently implanted, give off radiation for weeks or months. Their presence causes little discomfort, and they remain in the prostate after decay of the radioactivity. For several weeks following needle insertion, patients may experience pain in the perineal area, and urine may have a red-brown discoloration.
Although, when performed correctly, radioactive seed implantation may provide several benefits as compared to prostate removal and other techniques, current surgical apparatuses and methods for delivering the seeds to target locations within the prostate are somewhat crude and are subject to practitioner error. U.S. Pat. No. 5,871,448 Ellard, for example, describes apparatus similar to that currently in widespread use. The apparatus includes a needle template with a template holder. The template may be moved longitudinally along a track to alter the distance between the template and a patient""s perineum. The template holder is then rigidly affixed to the track, and brachytherapy needles are passed through the needle template to stabilize the needles prior to insertion through the patient""s perineum. A drawback of the Ellard device is that, apart from longitudinal adjustment, a medical practitioner is not able to alter the orientation of the template.
U.S. Pat. No. 5,957,935 Brown et al. describes a disposable needle template that need not be painstakingly sterilized. It further discloses a mount for the template that may be oriented in multiple planes. Specifically, the template may be positioned longitudinally, horizontally, and vertically. Although Brown""s apparatus may provide improved needle template orientation capabilities as compared to Ellard""s apparatus, it permits constrained movement, and does not allow simultaneous reorientation in multiple planes, as is necessary to change the angle of attack between the template and the patient.
A preferred angular orientation of the needle template may vary from needle to needle during a procedure due to anatomical constraints, including skeletal structures. Thus, a template that allows only one angular orientation is not optimal and may lead to incorrect placement of radioactive seeds within a patient""s prostate.
U.S. Pat. No. 5,626,829 Koutrouvelis provides a stereotactic assembly for orienting a template vertically, horizontally, rotatably, and angularly. While the assembly may be effective for the transgluteal brachytherapy procedure described by Koutrouvelis, it is not tailored for the more commonly used transperineal approach. For example, it does not provide for longitudinal adjustment of the needle template. Furthermore, the assembly is large and may prove cumbersome in the smaller surgical field of transperineal procedures.
In view of the drawbacks associated with orienting previously-known needle templates, it would be desirable to provide methods and apparatus that overcome such drawbacks.
It further would be desirable to provide methods and apparatus with improved orientation capabilities, sized to permit use in the surgical field of standard, transperineal brachytherapy procedures.
In view of the foregoing, it is an object of the present invention to provide methods and apparatus for orienting a needle guide that overcome drawbacks associated with previously-known methods and apparatus.
It is also an object of the present invention to provide methods and apparatus with improved orientation capabilities, sized to permit use in the surgical field of standard, transperineal brachytherapy procedures.
These and other objects of the present invention are accomplished by providing methods and apparatus for orienting a needle template comprising a template mount that provides for angular repositioning of the needle template with respect to an ultrasound probe. When used in conjunction with previously-known apparatus for longitudinal, horizontal, and vertical orientation of the template, the present invention provides superior control over needle template orientation without increased size, so that brachytherapy needles may be inserted in a manner that avoids skeletal structures. A guide tube is also provided to ensure xe2x80x9cstraightxe2x80x9d insertion of the brachytherapy needles.
Methods of using the present invention are also provided.